<!DOCTYPE html>
<html>
	<head>
		<meta charset="UTF-8">
		<title></title>
		<script>
			var pi = Math.PI;
			console.log(pi);
			var pq = Math.round(3.14); //四舍五入
			console.log(pq);
			
			var fool = Math.floor(5.2324); //取底 5
			console.log(fool);
			
			var ceil = Math.ceil(3.0001); //取顶 4
			console.log(ceil);
		</script>
	</head>
	<body>
	</body>
</html>
